Process of producing pyrophosphates



PEQCESS G1? PRODUCING PYROPHOSPHATES.

1 invention relnies 10 :1 'PZ'UCQSS of pro- 'iUi' ate; h-

simple and less really ii these hereiul m'e iiiupudcl ll'ilh lheiiz:mz'i miller ohjcvls in 'VlUW the iui'euliuu lfi ilrw in the um'el psand mnnhinzuimis: in" steps l'flllrlllllllflllf" the process iill :lsuill he inure lull v lierginul l'ei' diecarrying it cut than i, l

the more (-iem'ly' unelerslued ii, i said The umiuclimi u'lpyrhplwsphilln hf; "2h prim' nielhmle. with Whivh 1 {L111 familial has;im'ulHHl a1 winpnrnlively expensive and lwliuus: pmwduir in that thereagents mnplvyed zij'e more m less costly, and in so far llziinhu'qu-r, :1. continuous process has nut llll] l duped.

Unlw, 'lhe established methods 111:1) lie illuslr ilell by lhnleuipldvcd in the producliuu n1? nun. shin. pyi phusphule i 01 ex- :uuphyllilil which involves 'the l lllllillllllli cl' :1 saululiun clnmgg'nesiuni (flllOllli allgl 'l q will: :1 lu-liun elf acid sodiumphosphate liu ll i ll and unnnoniin whereupon a rein-,- iion lakes pla ein uccm'alunre will] l'he 'lnh hinting equutiunzinn mouiu in The, resull'ingr nm guesi um phosphate is then mleinell in predul-e l'hc (lenn'wlp crliphusphnie 1n aux-enhance Willi Specification of Letters Patent.

Amalieatlen filed fieptember 2%., 1919.

lfnlenled July liq, 1.

Serial No. 325.879.

first eq uztimn is exceedingly finely divided, and l'hcrel ore very hardto Wash.

in fan-t the entire process from an induslriul slizsnlli'minl isexpensive and also tincllicienl' in its results.

1 have llisrwn'ered on the other hand, that pyruphcsphales may hePIULlllLMl directly u'ilhuul rrnlcinnlinu and by :1. process; which isirzu-liirully continuous frmn a commercial. stzmdpuinl. ill suid newprocess will be he leiunllersluml when it is pointed out that iimanna-culciuiu phosphate is lire-uteri with :in ll ltl such for exampleas sulfuric acid, a: rear-lion takes lnce which may he indl- 7 Med 115lullcwsz- (all P ll-M1 80 The ym hosplmric acid HJLU lhus (ili-'l'zliumh huu'evur. will not remain as such in the presence of the waterof the reaction hut will combine with said water to produce in lheRllilllh the resulting compounds. That is in any, pyrophosphoric acidwill very quickly lake up Waite and change to orthophosphurie acid whenWater is present in any form zuul especially in Elie presence ofimpurilies, or other acids which seem to act as (-atnlym-rs tofacilitate he cemhinution ul' i yrnplmsphm'ic acid with Water.

ll follows from this that 110 pure pyrophosphute am be readily nnulefrom ym presplmric il 'lll. Whether the said ncid is nmde in the wellknown WA in ekpelling water first from oi'l'hophosphuric acid to makemet-ziphlisphoi-ir arid and then expelling the Water from the IULL'ZIPlHJSIAIOT C mill to lllfikP- 1))i'oplicsphoi'ic acid or byenipluyingz numo-mll'iuni phosphate or its kli lllYlilt'lll', for asshown :ihme, Said acid totally 01' in part. changes (0 orthophosphoi'icaeiil helim'e it run he made to coinl iul= Willi a liaise in make apyrophosphate.

* rsvrqling hu. in carrying out my invenice 0 upon inona'i-caln'ilh asalthavii iif 'nnd combined Willi ii 'lnzin wrepliespliorie acid, 30

that I get rid of the calcium constituent as well as the H t)constituent, in a. single operation, and produce a. pure pyrophosphateat once.

As an example of the'carrying out of my process I may take a solution ofmono-calcium phosphate, preferably of about 20 "36., and at atemperature say not exceeding (30 U., and pour the same into a solutionof magnesium acetate, i\Ig(C H,,(),) of about the same teinpta'aturc,and of the proper strength to complete the reciprocal interchange of theacid and basic ions ol" the salts to the end that a precipitate 0tmagnesium pyrophosphate Mg ll t will he produccd.

The solution will contain a mixture of calcium acetate and acetic acidas will. be clear from the. l'ollowii'ig equation T have furtherdiscovered that the toregoing principles are applicable to a largenumber of metal, and other salts, having a more strongly lasic ion than.calcium combined with a weaker acid than pyrophosphor'- acid. so thatthey will react in the sameway and give insoluble pyrophosphates. In butI have found that the acetates of the metals in general and semimetalsare particularly suitable to this process. \Vhen acetic acid is employedit forms calcium acetate mixed with acetic acid and it is very *asilypressed or washed out, or otherwise separated from the precipitatedpyrophosphate.

Furthermore, the solution containing the mixture of calcium acetate andacetic acid can'be used to make new acetates and thus the processcontinued. Should carbonates ot the metals be employed in connectionwith. the acetic acid and calcium acetate solutions. a hy-product ofcalcium carbonate is produced and it can he mixed with themoi'io-calciuin phosphate. For example, I may make an acetate from thesolution con taining the mixture of calcium acetate and acetic acid inaccordance with the following equation 2- Hence the resulting solutioncontaining the Mgtldtj), can he used again with the mono-calciumphosphate in accordance with the procedure set forth above. I find itadvantageous to allow the mixture of mono calcium phosphate and the acidto stand quite a while after the reactions are complete because thepyrophosphate will take on water ol crystallization and form a fineprecipitate of the spherical crystal form which is larger in size andmuch moreeasily washed free From the calcium acetate and the acetic acidin the solution.

It will now he clear from the foregoing that my method of producingpyrophosphates is more simple than the prior methods, and that the said1)yrophosphates are made in substantially one step or reaction, whilethe other methods require two or more, steps or reactions.

Many other examples of my invention could be given wherein reactionsinvolving othe' acid ions than those of acetic are cmployed, but it isbelieved that the above will be sullic'ient to show that the ions oforganic acids derived from soluble organic salts in general are to heexpected to Function in such a manner as to produce the correspoi'ulingpyrophosphates -wlien they react on mono-calciun'i phosphate.

'lheretore, it will be obvious that those skilled in the art may varythe details of the process as well as the constituents employed withoutdeparting from the spirit of the. invention, and accordingly. I do notWish to be limited to the above disclosure except as may he required bythe claims.

What- I claim is:-

'1. The process of making pyropluisplnites from monowalcium phosphate,which consists in reacting upon the latter with a salt having a strongerbasic ion than the cal cium ion present and a w .ilktl acid ion thanthat of 1iyrophosphoric acid, substantially as described.

2. The process of making a pyrophosphate from i'nono-calcium phosphate.which consists in reacting on the latter with an acetate having astronger basic ion than the calcium ion present, substantially asdescribed.

3. The process of: making magnesium pyrtqihosphate which consists inreacting on nmno-calcium phosphate with magnesium acetate. substantiallyas described.

4;. The process of making magnesium pynqihosphate which consists inreacting on m mo-calcium phosphate of substantially 20 36., withmagnesium acetate at a temperature of substantially (30" U,substantially as described.

l n testimony whereot'l aliix my signature, in presence. of twowitnesses. I

IlYLlliVlnN AlilSUN \V E BSTE R. lVitnesses:

R. M. MurrlN, N. A. GRAY.

